We asked Regency author Karen Harbaugh for a simple definition of a Regency romance, as opposed to a romance set in the Regency era. Here is what she had to say:

Strictly speaking, the Regency lasted from 1811 to 1820 in England, when the Prince of Wales took over for his father who was becoming insane. However, it's fairly flexible, and there have been Regencies (including Georgette Heyer's) that have been set as early as 1800.

The Regency romance really started when Georgette Heyer wrote her historicals set in Regency England. They weren't called Regencies then. Some folks will claim that Regencies started with Jane Austen, but that's wrong. She wrote contemporary romances--set during her own time--whereas Regencies are basically written of a time long gone.

They aren't written in the style of the 1800's regardless of what Regency fans try to say. They are written in a style that is somewhat similar to the way Georgette Heyer wrote them. There's a Regency "tone" to the books-- and I don't mean convoluted sentences and boring prose which, unfortunately often happens--that is somewhat difficult to define. The best example is that of Georgette Heyer; others are Clare Darcy, Edith Layton, and so on. I guess the tone is somewhat more. . . formal, I suppose, though that's not quite it, either. You definitely have to have your characters talk like the English, not Americans. For example, it's not likely that a Regency hero would say, "What the hell do you think you're doing?" He'd probably say, "What the devil are you doing?"

You'd never have a character in a Regency call another one a control freak, as one very awful Regency book I once encountered did. Also, there are some particular rules for the behavior of your characters-- they do have to be pretty historically accurate, or at least close to what Georgette Heyer had, which frankly is more Victorian in manners than Regency. Those Regency folk were pretty randy, to tell the truth. The way my hero and heroine act in my vampire book is closer to the way they acted back then than the your traditional Regency romance.

Anyway, in Regencies, for example, once the couple is engaged, you can't have the man back out of it--he'd be considered a cad, and the woman's reputation would be put into question. She'd be the one who'd have to break the engagement. A young woman generally didn't walk down Bond Street in London alone unless
she wanted a ruined reputation. She could wander about alone in the country, however, on her family's or a friend's estate. Things like that.

In my humble opinion, there really isn't much difference between a Regency and a Regency - set historical, except that Regencies are shorter, and do stick more closely to historical detail in general than historicals, especially where dialogue and behavior are concerned. Tell you the truth, you could have a long Regency, make it sensual, and it'd sell just fine as a historical.